You don’t hear much about occupational cancer. You hear about
cancer the tragedy for the individual, cancer the challenge for the
medical profession, cancer the result of smoking and bad diet.

But at least one in every 10 cancers – and probably many more
– are the result of preventable, predictable workplace exposures.
The International Labour Organisation’s estimate of over 609,000
work-related cancer deaths worldwide each year is almost certainly
a substantial under-estimate, but still amounts to one work-related
cancer death every 52 seconds.

Asbestos is the biggest industrial killer of all time, and kills
thousands from cancer every single week, at least one death every
five minutes. But it is not banned worldwide.

Dozens of other substances known to cause cancer are used, quite
literally, in industrial quantities in our workplaces, frequently
with few controls. This is not yesterday’s problem. At work,
we face a barrage of rapidly evolving substances, work methods, processes
and environments with little thought given to the health consequences
that will face society – workers, families, entire communities
- a working generation down the road.

Because today’s exposures cause cancers at least two decades
later, it is a problem that doesn’t cause alarm bells for corporate
executives who are answerable to shareholders from annual general
meeting to annual general meeting. Instead, the causes are covered-up,
the bodies are buried and the killing continues.

Key work cancer facts

• Occupational cancer is the top work killer worldwide,
ahead of all other workplace diseases and accidents.

• Over 600,000 workers die of occupational cancers ever
year, according to ILO – that’s one death every
52 seconds. The true toll is certainly much higher.

• More than 1 in 5 workers faces a cancer risk from their
work.

• Between 8 and 16 per cent of all cancers are the result
of exposures at work.

• Approaching 100,000 chemicals are used in workplaces
worldwide. Barely 1 in a 100 has been thoroughly tested for
health risks.

• Over 50 substances are rated by the United Nations’
International Agency for Research on Cancer (IARC) as a definite
or probable cancer risk at work. Over 100 more are IARC rated
as a possible cancer risk.

• Most causes of cancer were identified in studies of
workers.

• It is not just industrial workers that are at risk.
Hairdressers, teachers, nurses, doctors, farm and office workers
and workers in many other jobs have also died of occupational
cancers.

• Tens of thousands of workers generally have to die
before scientific studies identify a workplace cancer problem.
A precautionary approach is always the safe and healthy option.

Burying the evidence

The world is facing a cancer epidemic which has been almost entirely
missed in official statistics. Occupational cancer is killing thousands
worldwide every day, but is not receiving adequate attention from
workplace enforcement or public health bodies. Cancer is a very modern
killer. Lung cancer reports were relatively rare at the start of the
21st century.

The massive increase in smoking in the 20th century was an indisputable
and major cause of the lung cancer explosion. But coincident with
the explosion in smoking, was an explosion in workplace exposures
to a continually widening pool of workplace substances that had been
poorly studied and which were, for much of the century, poorly controlled.
There are now approaching 100,000 synthetic chemicals used in our
workplaces. Many more people today are exposed to many more substances.

While smoking cessation has become a major public health priority
and has spurred an entire prevention industry, no similar campaign
has been waged to address the carcinogens encountered and inhaled
by millions at work. The International Labour Office (ILO) ranks occupational
cancer as the top work-related cause of death worldwide, accounting
for almost a third of all deaths linked to workplace factors, more
than circulatory disease, infections or accidents.

Primary prevention – removing the risks – could prevent
all occupational cancers. But wherever you work, too little official
regard for the risks has meant precious little regard for prevention.

What kills at work?

A January 2007 paper in the American Journal of Industrial
Medicine gives a breakdown of the top workplace killers. The
major causes identified are:

Working out the relative contribution of lifestyle, diet, pollution,
occupation and other factors to the overall cancer toll is at best
informed guesswork. In a move that has led to occupational cancer
being a forgotten prevention priority, governments routinely cite
a 1981 report to the US Congress – the Doll/Peto report (1)
- which estimated that 4 per cent, with a range of certainty of 2
per cent to 8 per cent, of cancer mortality was due to occupational
causes.

The
lead author, Professor Sir Richard Doll, was at the time receiving
substantial undeclared payments from industry, including major chemical
producers and a top US chemicals trade body. And the findings just
didn’t add up. Large swathes of the at-risk workforce were excluded
from the analysis. Retired workers were excluded too – despite
being the workers most likely to develop work-related cancers. Far
more people are exposed to far more substances than they were willing
to admit.

Women scarcely featured in the large industrial US workplaces considered
by the study, and breast cancer – a major killer in women –
is ignored. And African-American workers, concentrated in the most
hazardous manual jobs, were excluded entirely from the analysis. But
this isn’t the whole story. Not everyone is at risk. The great
majority of occupational cancers are concentrated in blue collar jobs,
meaning those workers face a massively increased risk, while others
face virtually none. For some workers in some jobs – certain
asbestos and rubber industry workers, for example - work was in effect
a death sentence.

The
widespread, unquestioning, acceptance by governments of the Doll/Peto
low figure for the occupational contribution to total cancer causation
was good news for some, but a death sentence for others. “The
companies were ecstatic when Doll/Peto came out, because it posed
the whole thing politically as a lifestyle issue,” Stirling
University occupational cancer authority Dr Jim Brophy(right) said.
“That had consequences for prevention, in that it effectively
ended any chance of a structured and well resourced strategy to combat
occupational cancer.”

Thousands have gone on to die from cancers they just shouldn’t
have developed, at least according to the Doll/Peto estimate, including
the family members of workers exposed to asbestos, who got a second
hand “paraoccupational” dose from the contaminated clothes
and hair of a family member.

Recent reassessments of the real work cancer toll in the US, Australia,
the UK and elsewhere have given some indication of how far Doll/Peto
fell short of the real risk.

Studies of actual work-related cancer levels have put the true contribution
of work to cancer deaths at up to five times the level reported by
Doll/Peto. A World Health Organisation report in 2006 (2)
said: “The estimates of the proportion of cancer deaths in the
general population attributable to occupational exposures in developed
countries are in the range of 4-20 per cent.” It added: “Occupational
cancer is entirely preventable and interventions at the workplace
can save millions of lives every year.” Recent reviews suggest
a workplace contribution of between 8 and 16 per cent of all cancers
(3).

An International Labour Organisation (ILO) estimate, cited in the
American Journal of Industrial Medicine in January 2007,
concluded the attributable fraction of occupational cancers in industrialised
countries is 13.8 per cent for men and 2.2 per cent for women. ILO’s
cautious estimate puts the global human toll at over 600,000 deaths
a year – one death every 52 seconds (4).
This would translate to around 10 per cent of all cancer deaths every
year.

The authors, which included the then director of ILO’s Safework
programme, concluded that while at the moment the relative importance
of cancers as a cause of work-related deaths is higher in developed
nations, the export of hazardous jobs and processes as a component
of rapid industrialisation meant “developing countries are encountering
work-related hazards more frequently than developed countries did
at the time of their industrialisation, which took place over a relatively
long time period. Work-related diseases will grow in relative significance
in the future as a component of the morbidity and mortality of society
as a whole.”

A 2006 paper in the Australian and New Zealand Journal of Public
Health(5)
contained an explicit criticism of the Doll/Peto figures. The authors
reported: “Because of outdated data, and gaps in knowledge of
which chemicals cause cancer and the magnitude of the risk of cancer
from each carcinogen, these are very likely to have been considerable
underestimates.” They add: “We estimate that approximately
10.8 per cent of cancer cases (excluding non-malignant skin cancers)
in males and 2.2 per cent of such cancer cases in females are caused
by occupational exposures.”

According
to Dr Richard Clapp (right) of the University of Boston Medical School,
USA, co-author of the September 2005 review (6):
“Using the 1981 Doll/Peto estimates for occupational cancer
probably underestimates the occupational exposure contribution by
a factor of two to four in both the US and the UK.”

Dr Clapp said: “I believe occupational lung cancer is the leading
work-related cancer followed by bladder cancer, non-Hodgkin's lymphoma,
and leukaemia. Our review paper gives the scientific studies which
back this up, along with the various exposures that cause these cancers.

“For example, for lung cancer, we review the evidence that
metals, solvents, ionising radiation, reactive chemicals like BCME,
environmental tobacco smoke, air pollution, polycyclic aromatic hydrocarbons,
pesticides and fibres like asbestos and silica cause lung cancer.
This adds up to a substantial burden, and some of these exposures
- like asbestos and ionising radiation in underground miners - act
synergistically with cigarette smoke and vastly increase lung cancer
risk.”

He added “there is no way to put a precise number on this because
cancer is such a ‘multifactorial’ disease and even small
exposures can be a critical piece of the pie when lots of people are
exposed. The reason we have so much cancer is because we are exposed
to so many carcinogens; we need to turn that around both by producing
and using fewer carcinogenic materials and not exposing workers and
others to them.”

Dr Samuel Epstein, emeritus professor of environmental and occupational
medicine at the University of Illinois at Chicago, puts the occupational
figure in the Clapp range, saying “based on minimal estimates”
occupational carcinogenic exposures are responsible for 10 per cent
of overall cancer mortality adding that for certain occupational exposures,
mortality rates are much higher (7).

He said “lifestyle academics” including Sir Richard Doll
“have consciously or unconsciously become the well-touted and
enthusiastic mouthpiece for industry interests, urging regulatory
inaction and public complacency”, adding the “puristic
pretensions of ‘the lifestylers’ for critical objectivity
are only exceeded by their apparent indifference to or rejection of
a steadily accumulating body of information on the permeation of the
environment and workplace with industrial carcinogens and the impact
of such involuntary exposures on human health.”

According to Epstein, any adherence to the Doll/Peto figures is folly
because their paper “excluded from analysis people over the
age of 65 and blacks, just those groups with the highest and increasing
cancer mortality rates. Not content with such manipulation, they claimed
that occupation was only responsible for 4 per cent of all cancers,
without apparent consideration of a wide range of recent studies dealing
with the carcinogenic effects of such exposures… The wild 4
per cent guess was matched by ‘guesstimates’ that diet
was determinant in some 35 per cent of all cancers.”

Professor
Andy Watterson (right) of Stirling University’s occupational
and environmental health research group, believes Clapp’s estimate
of real occupational cancer incidence “is about right”.
He added: “Lung cancers caused by asbestos exposure are not
picked up and other occupational cancers simply do not show up on
the official radar; the contribution of work to breast cancers is
widely neglected and there are a number of carcinogens that attack
humans – brain, nervous system, soft tissue sarcomas, cancer
of the larynx, kidneys, stomach, bone – which are not adequately
regulated.”

Learning lessons

Asbestos is the world’s biggest ever industrial killer.
Studies suggest asbestos disease could eventually account for
10 million deaths worldwide (8).
At least 100,000 die each year – one person every five
minutes.

Despite its deadly history, there is no worldwide ban and there
is even evidence asbestos production could be increasing. While
many richer nations will no longer tolerate its use and have
introduced stringent laws controlling the asbestos that remains
in workplaces, the same cannot be said for developing nations.
And it is these nations that are being targeted by the global
asbestos industry lobby.

Asbestos cancer rates are still climbing in many industrialised
nations. Unless we learn the lessons of these deaths, we’ll
see a new generation killed by new epidemics – same tragedy,
different location. There are signs we can stop history repeating
itself. After a high profile union campaign, international organisations
including the International Labour Organisation (ILO) and the
World Health Organisation (WHO) are now backing the union call
for a worldwide ban.

It took decades of campaigning to get this far with asbestos.
But we are still introducing new substances and new technologies
– for example, nanotechnology – to workplaces without
the necessary investigations and precautions. We are already
seeing raised cancer rates in some computer factories, a supposed
“clean industry” which is just one working generation
old.

It can take a generation of exposures and a generation of deaths
for traditional studies to spot an occupational cancer risk, unless
the cancer is very rare in the general population. With the exception
of the asbestos cancer mesothelioma, however, the most common occupational
cancers are also common in the wider community.

New industries are emerging all the time, providing potential new
processes and new exposures. Little is known about the possible long-term
health effects the of vast number of nano-products in development
or already in production, for example, but the lesson of history is
that today’s wonder product can be tomorrow’s toxic nightmare
(9).

Without a precautionary approach to the substances we use and the
environments we create at work, we risk condemning thousands of workers
to preventable deaths. Still, occupational cancer remains a low priority,
with a misconception that better understanding and better regulation
have relegated occupational cancer to a lingering but fast decline
dangerous legacy of past practices and exposures.

In fact, regulation has not been a cancer cure. Unlike the case of
infectious diseases, where a response is frequently swift and draconian,
there are typically long delays between the identification of a carcinogenic
agent and adoption of adequate measures of prevention. Even then,
measures are usually late and incomplete, and will leave a generation
to await their fate as a result of prior exposures.

Instead, the assumption that it is “the dose the makes the
poison” has been behind a piecemeal and slow, incremental reduction
in workplace exposure limits, for workplaces where carcinogens are
handled, quite literally, in industrial quantities. For many substances
this presumed dose-response relationship is dangerous flawed.

The asbestos related cancer mesothelioma is a case in point, occurring
now in people who had only incidental exposure to asbestos. Only a
handful of workplace substances have ever been banned on grounds of
carcinogenicity. Most countries still allow the use of asbestos products,
despite it being the most prolific ever industrial killer which may
claim 10 million lives before it is banned worldwide (8).
An early, precautionary move to safer alternatives would have saved
millions. Commercial interests ensured that did not happen.

While official agencies worldwide have stuck with Doll/Peto’s
1981 estimates of risk, a generation has gone by and new evidence
has come to light, including evidence for cancers dismissed entirely
by the report or only included in very limited circumstances.

A 2004 paper reported the risk of ovarian cancer increases with increased
exposure to diesel exhaust at work. It found individuals with the
highest cumulative exposure to diesel exhaust had more than 3.5 times
the risk of ovarian cancer (10).

A 2005 paper concluded exposure to wood dust increased the chances
of developing not only nasal cancer but also lung cancer, finding
the risk of lung cancer was increased by 57 per cent with wood dust
exposure in absence of smoking, by 71 per cent for smoking in the
absence of wood dust exposure, and by 187 per cent for individuals
who were exposed to both smoking and wood dust (11).

A September 2005 paper concluded exposure to polycyclic aromatic
hydrocarbons (PAHs) dramatically increased the risk of laryngeal cancer,
up by 5.2 times (12).
A 2004 paper linked workplace exposure to the pesticide chlropyrifos
to a doubling of the lung cancer risk (13).

And a slew of papers have linked occupational factors to the development
of gliomas, including exposure to arsenic, mercury and pulp products
(14), work
in pulp mills (15)
and other occupations (16).

Firefighters have a clearly increased risk of cancer caused by exposures
at work, studies have shown. A November 2006 analysis of 32 US and
European studies covering 110,000 firefighters found rates of testicular
cancer were 100 per cent higher and prostate cancer 28 per cent higher
than expected. There was also a 50 per cent increasing in non-Hodgkin’s
lymphoma and multiple myeloma (17).

On 31 October 2005, the Canadian province of British Columbia (BC)
followed other provinces and recognised leukaemia, brain cancer and
five other kinds of cancer as occupational hazards for long-time firefighters.
The new law recognises primary site brain cancer, primary site bladder
cancer, primary site kidney cancer, primary non-Hodgkin’s lymphoma,
primary site ureter cancer, primary site colorectal cancer and primary
leukaemia as occupational diseases associated with long-time work
as a firefighter.

This change to the BC Workers Compensation Act creates a “rebuttable
presumption” which means the onus will be on compensation authorities
or the employer to bring forward proof to establish why a worker should
not be eligible for compensation rather than placing the burden of
proof on a sick firefighter. Similar presumptions have been enacted
for firefighters in the provinces of Alberta, Manitoba, Saskatchewan
and Nova Scotia.

Across much of Canada and in parts of this US this risk is legally
recognised and officially compensated (18),
although firefighters elsewhere are rarely compensated or warned of
potential risks. But for jobs with less obvious, visible exposures,
the chances of a warning or any hope of compensation are usually far
more remote. Yet even with “clean” technology and improved,
modern, workplace safety practices, the risks can be real.

A 2006 US study found staff employed at IBM computer factories, using
the firms own ‘Corporate Mortality File’, had high rates
of a range of cancers, linked to exposures to chemicals and electromagnetic
fields (19).
Studies have found similar problems in computer factories in other
countries (20).

Cancers
“significantly greater” in computer factories

Staff at computer factories could be at increased risk of contracting
cancer because of working environments containing high levels
of chemicals, metals and electromagnetic fields, according to
findings of a long suppressed US study (19).

IBM fought for several years to prevent release of the study
done by Richard Clapp, a Boston University professor of environmental
health. The study analyses data collected by IBM itself on the
ages and causes of death of nearly 32,000 people who had worked
at IBM and died between 1969 and 2001. Dr Clapp got hold of
the data, known as IBM's “Corporate Mortality File,”
as an expert witness who analysed it for lawyers in California.
They had sued IBM on behalf of a number of workers at a disk-drive
plant in San Jose who got cancer.

The study looked at death records of men and women who had
worked for IBM for at least five years. It found in men the
cancer risk was “significantly greater” than the
national average. Several individual cancers showed particularly
high rates, including cancers of the digestive organs, kidneys,
brain and central nervous system and malignant melanoma of the
skin. In women, breast cancer, lung cancer, genital cancer,
brain and nervous system cancers rates were all elevated.

Occupational health specialists in the UK say the findings
should be a warning sign. Professor Andrew Watterson of Stirling
University said similar results had been found in Scotland’s
National Semiconductor plant. He said: “The US study confirms
some of the evidence we have seen at Nat Semi. The families
of former Nat Semi workers have been calling for years for a
Europe-wide or international study into the industry, and this
is the next best thing.”

What causes work cancer?

A September 2005 University of Massachusetts Lowell report
(6)
identified examples of “strong causal links between environmental
and occupational exposures and cancer”, many of which
are commonly encountered in UK workplaces today, including:

• Metals such as arsenic, chromium and nickel and cancers
of the bladder, lung, and skin.

• Chlorination byproducts such as trihalomethanes and
bladder cancer.

• Natural fibres such as asbestos and cancers of the
larynx, lung, mesothelioma, and stomach.

• Petrochemicals and combustion products, including motor
vehicle exhaust and polycyclic aromatic hydrocarbons (PAHs),
and cancers of the bladder, lung, and skin.

• Ionising radiation and cancers of the bladder, bone,
brain, breast, liver, lung, ovary, skin, and thyroid, as well
as leukaemia, multiple myeloma, and sarcomas.

• Solvents such as benzene and leukaemia and non-Hodgkin’s
lymphoma; tetrachloroethylene and bladder cancer; and trichloroethylene
and Hodgkin’s disease, leukaemia, and kidney and liver
cancers.

• Environmental tobacco smoke and cancers of the breast
and lung.

Industry wins, workers lose

The result of governments and statutory agencies failing to recognise
the real extent of the occupational cancer problem, instead reproducing
as “fact” now discredit estimates based on bad research
on US workplaces over a quarter of a century ago, has been a wholly
preventable public health disaster. Many occupational carcinogens
are still encountered regularly in the workplace and today’s
working generation is still being exposed to substances and environments
that will cause tomorrow’s cancers. And the risk of exposure
may, in fact, be increasing.

Figures from the French national statistic office DARES published
in 2005 revealed more than 1 in 8 workers was exposed to workplace
substances that can cause cancer. The analysis of the 2003 SUMER survey
indicated that 13.5 per cent of the total French workforce was exposed
to one or more of a list of 28 workplace carcinogens (21).
The figure was higher than estimates a decade earlier. Blue collar
workers were eight times as likely to be at risk, with 25 per cent
exposed. Eight products, all common in UK workplaces, contributed
more than two-thirds of all exposures – mineral oils, three
organic solvents, asbestos, wood dust, diesel exhaust fumes and crystalline
silica.

The World Health Organisation (WHO) ‘Global burden of disease’
study in 2002 (22)
concluded 20-30 per cent of males and 5-20 per cent of females in
the working-age population could have been exposed to an occupational
lung cancer risk during their working lives, for example, asbestos,
arsenic, beryllium, cadmium, chromium, diesel exhaust, nickel and
silica.

The European Union’s CAREX database of occupational exposures
to carcinogens estimated that in the early 1990s 22-24 million workers
in the then 15 European Union member states were exposed to possible
carcinogens. The most common exposures were solar radiation, environmental
tobacco smoke, crystalline silica, radon and wood dust (23).

Overall, 32 million workers, 23 per cent of the working population,
had workplace exposures associated by the CAREX database with an occupational
cancer risk. The most common exposures were solar radiation, environmental
tobacco smoke, crystalline silica, radon and wood dust.

Occupational cancer is a global problem and could grow in significance.
‘Global estimates of fatal work-related diseases’, a January
2007 paper in the American Journal of Public Health co-authored by
the then-head of ILO’s Safework programme, concluded: “The
proportion of malignant neoplasms [cancers] and circulatory system
diseases is significant in almost all regions, and it might still
grow in the future because the proportion of communicable diseases
is expected to diminish.”

According to the paper, occupational cancer is in both the established
market economies far and away the most common cause of occupational
disease fatalities, causing over half of the deaths. It was the top
cause of work-related death in China, too. That over 1 in 5 workers
face a workplace cancer risk shouldn’t be a surprise. About
95 per cent of causes of lung cancer were identified in workplace
studies, and if you discount drugs over threequarters of all causes
of cancer were identified in studies of workers (24).

Cancers and their work causes

Cancers associated in studies with exposures to workplace substances
include the following.

Kidney cancer Evidence sketchy
because of high survival rates, but some links to arsenic, cadmium
and lead; solvent exposure, particularly trichloroethylene;
petroleum products; pesticides linked to Wilms’ tumour
in children, and to the children of fathers employed as mechanics
or welders.

Laryngeal cancer Metalworking
fluids and mineral oils; natural fibres including asbestos;
some evidence for wood dust exposure; exposure to reactive chemicals
including sulphuric acids. Excesses seen in rubber workers,
manufacture of mustard gas, nickel refining, and chemical production
using the “strong acid” process.

Prostate cancer Links to cadmium,
arsenic and some pesticides, notably herbicides and other endocrine
disrupters. Excess risks have been found for exposure to metallic
dusts and metalworking fluids, PAHs and liquid fuel combustion
products, and farmers and pesticide applicators.

Rectal cancer Metalworking fluids
and mineral oils. Some evidence for solvents, including toluene
and xylene.

Testicular cancer Evidence for
endocrine disrupting chemicals (eg. phthalates, PCBs and polyhalogenated
hydrocarbons). A literature review found significantly elevated
risks in men working in industries including agriculture, tanning
and mechanical industries, and consistent associations with
painting, mining, plastics, metalworking and occupational use
of hand-held radar.

Even if we evaluate all the available evidence, we may not be evaluating
the evidence we need, or evidence that honestly reflects the real
occupational risks. According to Stirling University’s Dr Jim
Brophy: “The reaction of manufacturers that produce or employ
products that might be deemed to be carcinogenic has at times been
to suppress the damning research rather than to take steps to prevent
harm to the exposed populations.”

Dr James Huff, who headed IARC’s chemical evaluation programme
until 1980, said in 2003 that the agency had lost its position as
“the most authoritative and scientific source” on cancer
risks “due to the increasing influence of those aligned with
the industry point of view regarding chemicals and their inert hazards
to public and occupational health.” He found representatives
with industry sympathies or affiliations routinely outnumbered those
aligned with public health at IARC evaluation meetings (25).

In the decade from 1993, ratings for eight chemicals were upgraded,
but 12 were downgraded. In the preceding decade, before industry asserted
its influence on the decision making process, no IARC assessments
were downgraded. In fact it can take a concerted campaign to get action
to prevent cancer risks, even when the evidence of harm is overwhelming.
A lowering of the maximum permissible workplace exposure levels for
benzene was strongly opposed by industry, which is still resisting
recognition of the risks of low concentrations (26).

According to Dr Lorenzo Tomatis, who headed the IARC programme until
1993, industry is now dictating terms. “The prevailing assumption,
also used as an improper justification, was that the production of
certain goods is necessary and vital, even when it was only aimed
at increasing consumption of inessential goods, and that the risks
involved in their production are an unavoidable price that society
must pay.”

He said this “disregarded the evidence that the highest price
is paid by a particular sector of the population, in which morbidity
and mortality are considerably higher than those in the rest of the
population.”

An unjust public health disaster

This unequal risk of occupational cancer means a minority of the
population are facing an enormously elevated, serious and preventable
risk. That risk is not being taken seriously and those cancer cases
are not, on the whole, being prevented. Work-related cancer is far
more common in blue-collar workers – there is an undeniable
correlation between employment in lower status jobs and an increased
risk (24).

Studies have found, for example, that 40 per cent of the lung and
bladder cancer cases in certain industrial groups can be caused by
occupational exposures (27).
French statistics office figures published in 2005 found 1 in 8 workers
were exposed to carcinogens at work, but that the figure was 25 per
cent for manual workers and just 3 per cent for managers (29).

And the exposures causing these cancers are not the result of informed,
lifestyle choices. They are the consequence of being required to spend
the working day in a place that contains carcinogens and where decisions
about how they are used and controlled are almost entirely outside
the influence of the person facing the risk.

The World Health Organisation’s occupational health and safety
newsletter in 2006 said “affects certain groups of the society
much more than others. Furthermore, occupational risks for cancer
are taken involuntarily, as opposed to some major lifestyle risks.”
(2).

The asbestos cancer mesothelioma is one of the most stark examples.
A 2004 British Medical Journal editorial on the UK asbestos
cancer epidemic noted: “For a man first exposed as a teenager,
who remained in a high risk occupation, such as insulation, throughout
his working life, the lifetime risk of mesothelioma can be as high
as one in five. There are now over 1,800 deaths per year in Britain
(about one in 200 of all deaths in men and one in 1,500 in women),
and the number is still increasing” (28).

According to the 2005 UMASS Lowell report (6):
“Unequal workplace exposures among different populations provide
further indications of the ability of occupational exposures to cause
harm.” It adds that studies in the US steel industry found the
highest rates of lung cancer – 10 times expected – were
in non-white workers, employed in the highest risk jobs. This racial
inequality in occupational cancer risks has been reported in a number
of studies (29).

Long-term benzene workers are 30 times more likely to die of leukaemia,
the UMASS Lowell report says, and adds: “More than half of asbestos
workers have died of cancer and the relative risk of lung cancer among
asbestos workers who smoke is 55,” or 55 times the general level
in the population.

According to the CAREX report for Great Britain (30),
all the workplace exposures to carcinogens were restricted to about
one-fifth of the working population. If the occupational cancer risk
was equal across the population, based on HSE’s figure of 6,000
deaths a year, this would equate to 1 per cent of all deaths being
caused by occupational cancers in any given year. However, the responsible
exposures are limited to a much smaller group who bear most of the
risk, suggesting that 5 per cent or more of deaths in this group could
be caused by occupational cancers.

The 2006 WHO report (2)
made a similar point. “Occupational cancers concentrate among
specific groups of the working population. For those people the risk
of developing a particular form of cancer may be much higher than
for the general population. For example, an estimate of a 3 per cent
of total cancer deaths due to occupation in the general population
may increase to 12 per cent in the very broad category of male blue
collar workers and up to 80 per cent among populations exposed to
carcinogens.”

According to Stirling University’s Dr Jim Brophy: “Even
the lowest estimates of occupational cancer risk for the overall population
translate to a 25 per cent risk in the exposed population. I think
work-related cancer is being diluted as workers at high risk are thrown
in with the general population. A revised public health strategy would
emphasise government regulations and accountability to curtail worker
and community exposures to carcinogens rather than relying on individual
behaviour modification or allocating the bulk of research cash to
discovering a cure for cancer.”

It is not just about prevention of cases of occupational cancer,
it is also about efforts to make sure those cancers do not kill. For
now, occupational cancer remains a virtually invisible killer. Those
who have already faced the exposures that will result in them developing
cancer are not being told of that risk and are not getting the surveillance
that might allow an early and possibly lifesaving intervention.

Stopping work cancer dead

Brophy is among a growing body of occupational health professionals
who think the Doll/Peto carve up of cancer by cause did a disservice
to prevention efforts, not just by getting it wrong, but by failing
to fully reflect the complexity of cancer causation. “The reason
we don’t see any of the occupational cancers other than mesothelioma
is because at any time there are multiple causes, and where the default
designation is ‘lifestyle’.”

His colleague at Stirling University, Professor Andrew Watterson,
agrees: “Good public health practice should now automatically
recognise the multi-causality of many cancers and the significant
part that work circumstances and related wider environmental factors
will play.

“Instead we continue to have a narrow, skewed and flawed focus
on lifestyle factors that ignore other exposures to carcinogens. This
may reflect government policy which bends to the wishes of employers,
pushes deregulation and doesn’t have an effective policy on
or properly resourced structure to address occupational and occupationally-related
cancers.”

The 2005 UMass Lowell report (6)
notes: “The least toxic alternative should always be used. Partial
but reliable evidence of harm should compel us to act on the side
of caution to prevent needless sickness and death. The right of people
to know what they are exposed to must be protected.”

If all carcinogen use in the workplace stopped today, there would
still be a working generation and hundreds of thousands of retired
workers that have already faced some level of risk. For this reason,
public health advocates are also arguing for more effective recording
of exposures and better recognition of the link between work and health.

“We should be filing compensation cases to get recognition
of the links between jobs and cancer and unions should be documenting
cases of illness among their members and looking for trends,”
says Dr Jim Brophy. “The health service should improve its act
too, and should be documenting occupational histories – if they
can document a person’s smoking and lifestyle habits, why not
the workplace risk factors too?”

Canadian campaign demands prevention

The Canadian Strategy for Cancer Control (CSCC), a coalition
of cancer prevention, health service and other bodies, has made
a public stand in favour of “primary prevention”
of occupational cancer.

A 12 October 2005 letter from CSCC’s National Committee
on Environmental and Occupational Exposures (NCEOE) called on
a House of Commons standing committee to back changes in Canadian
law to better promote preventive measures. It called for the
Canadian government to strengthen the Canadian Environmental
Protection Act as it is applied “in particular to IARC
1 and 2a designed human carcinogens.” The letter also
called for information bulletins to be developed to address
cancer prevention and toxic use exposure reduction, an investigation
of the possibilities for introducing toxics use reduction legislation,
and for possible incentives for toxic use reduction programmes.

A May 2005 NCEOE report identified seven priority areas for
improving primary prevention: improved surveillance; better
information disclosure and labelling; community education and
action; worker education and action; non-governmental organisations’
involvement in cancer prevention; employer/industry reductions
in carcinogen use; and government intervention in the form of
new regulations and policy.

Letter to Standing Committee on Environment and Sustainable
Development, House of Commons, Canada, 12 October 2005.

Prevention of occupational and environmental cancers in
Canada: A best practices review and recommendation. May
2005 [pdf].

Industry’s deadly research role

The effective identification of workplace cancer risks has slowed.
There’s good reason to believe this could be the result of a
well-coordinated industry campaign to influence decisions of bodies
including the International Agency for Research on Cancer (25)
and the World Health Organisation, rather than any actual improvements
at work.

And as public funding for independent occupational health research
is eroded, industry-funded research is swamping the literature, with
occupational and environmental risks going underestimated or undetected
as a result. A report in the October-December 2005 issue of the International
Journal of Occupational and Environmental Health (IJOEH) (31),
examining “business bias” in workplace studies, concludes
“in spite of claiming primary prevention as their aim, studies
of potential occupational and environmental health hazards that are
funded either directly or indirectly by industry are likely to have
negative results.”

The authors say “studies of workers in oil refineries conducted
with total economic independence have identified possible environmental
and health risks associated with exposures to more than 50 substances
classified as toxic, mutagenic, and carcinogenic, such as asbestos,
arsenic, benzene, chromium, nickel, polycyclic hydrocarbons, and silica.
The IARC has therefore evaluated exposures in oil refineries as probably
carcinogenic to humans. By contrast, other studies undertaken with
the same areas of industrial production, supported by industry and
of doubtful independence, do not report the existence of any risks.”

The authors add: “A review of studies of effects of exposures
to selected chemicals (alachlor, atrazine, formaldehyde, and perchloroethylene)
shows that 60 per cent of such studies conducted by non-industry researchers
found these chemicals hazardous, while only 14 per cent of industry-sponsored
studies did so…. Such studies have contributed to a harmful
delay in the adoption of preventive measures and have downplayed the
significance of primary prevention, especially in developing countries.”

The authors of studies critical of industry can find themselves facing
a barrage of attacks, both from lawyers and the industry’s own
PR machine. A second paper in the October-December 2005 issue of IJOEH(32) notes
corporations “work with attorneys and public relations professionals,
using scientists, science advisory boards, front groups, industry
organisations, think tanks, and the media to influence scientific
and popular opinion of the risks of their products of processes. The
strategy, which depends on corrupt science, profits corporations at
the expense of public health.”

The paper concludes: “The strategy developed by corporations
working in concert with law and PR firms has been successful in limiting
both liability and regulation.” It says concerned health professionals
and others have to wage their own PR campaign “to protect rather
an undermine public health” and “must form more effective
linkages with unions and authentic grassroots community organisations.”

How do you get exposed?

There are three main ways workers are exposed to a workplace
cancer risk – they can touch it, breathe it or swallow
it.

Epidemiology Counting the bodies
to see if there is a risk of disease.

ILO conventions

The International Labour Organisation (ILO) convention on occupational
cancer makes clear, commonsense recommendations which could and should
be followed everywhere. There’s good reason for occupational
cancer to be an ILO priority – its says it is the top cause
of work-related deaths worldwide, killing one person every 52 seconds.

The ILO cancer convention, C139, requires ratifying countries to:

• Periodically determine the carcinogenic substances
and agents to which occupational exposure shall be prohibited or made
subject of authorisation and control.

• Make every effort to replace carcinogenic substances and agents
with non-carcinogenic and less harmful alternatives.

• Take measures to reduce to the minimum the number of workers
exposed to carcinogenic substances, and the duration and degree of
exposure and to establish an appropriate system of records.

• Ensure that workers who have been, are, or are likely to be
exposed to carcinogens, are provided with information on dangers and
relevant preventive measures.

• Organise medical surveillance of workers at risk, during and
after employment.

By ILO’s estimate, one in every six workplace cancer deaths
is caused by asbestos exposure. The ILO asbestos convention, C162,
calls for action to minimise risks posed by asbestos. A resolution
agreed at ILO’s 2006 conference clarified the purpose of the
convention. It said “the elimination of the future use of asbestos
and the identification and proper management of asbestos currently
in place are the most effective means to protect workers from asbestos
exposure and to prevent future asbestos-related deaths.”

The 2006 resolution added that the convention “should not be
used to provide a justification for, or endorsement of, the continued
use of asbestos.” It instead called for efforts “to promote
the elimination of future uses of all forms of asbestos and asbestos
containing materials.”

ILO’s chemicals convention, C170, calls on employers to assess
the exposure of workers to hazardous chemicals; monitor and record
the exposures where necessary; maintain adequate records and ensure
they “are accessible to the workers and their representatives.”

Two major US reports published shortly before the Doll/Peto report
– one from US government organisations (33) and another backed
by employers’ organisations – put the occupational cancer
contribution at at least 20 per cent of all cancers, with the industry-backed
report conceding occupational cancer constituted “a public health
catastrophe” (34).

A major review of environmental and occupational causes of cancer
published in September 2005 (6)
concluded: “It is difficult to estimate the impact of Doll and
Peto’s views, but their 1981 article had been cited in over
441 other scientific articles by the end of 2004. More importantly,
it has been cited repeatedly by commentators who argue that ‘cleaning
up the environment’ is not going to make much difference in
cancer rates.”

While industry groups and HSE embraced the Doll/Peto estimates, others
were more critical. Hazards magazine warned in 1996 that the estimate
“was always suspect and is now totally discredited”. A
1995 paper in the Mt Sinai Journal of Medicine said the occupational
cancer figure was too low and added it failed to take account of the
limitations of the data on which it was based (35).

Occupational cancers by definition only occur in those of working
age and above and, because of latency periods before the development
of disease, many are likely to emerge in old age. We have an aging
population – as other causes of death decline more are likely
to survive long enough to develop their occupational cancers.

Doll/Peto not only top sliced the numbers, it only considered cancer
risks posed by a list of 16 substances or industries. The International
Agency for Research on Cancer (IARC), however, classifies 89 substances
as definite human carcinogens, 64 as probable human carcinogens and
264 as possible human carcinogens. A 2004 paper in the journal Environmental
Health Perspectives reported that this included 28 definite,
27 probable and 113 possible human occupational carcinogens (36).

Occupational cancer risks to women are almost entirely ignored in
the Doll/Peto analysis, which concentrated on jobs which in the preceding
decades had been largely the preserve of men (37).

And Doll/Peto excluded African-Americans from the analysis, a group
over-represented in high risk jobs and with higher and increasing
cancer rates.

The impact on occupational cancer incidence of the synthetic chemicals
produced in unprecedented volumes in recent decades would not have
been estimated in Doll/Peto’s analysis – this only considered
a small number of well established cancer risks - but could have been
predicted on the basis of limited human evidence and more extensive
toxicological and animal studies.

According to Dr Lorenzo Tomatis, who until 1993 headed the International
Agency for Research on Cancer (IARC) programme evaluating chemicals,
there is a marked double standard in operation when it comes to proof
of risk. “A necessary requirement for declaring an environmental
chemical carcinogenic to humans is that conclusive epidemiological
studies support a causal relationship, and particularly robust evidence
for an association between occupational exposure and human cancer
is required because a causal association is accepted, while the evidence
for a contribution of dietary factors to the cancer burden is usually
circumstantial and, in come cases, rather weak,” he said.

He told a Collegium Ramazzini conference in September 2005: “Punctilious
precision is used in calculating occupational and environmental risks,
while a wide latitude is allowed for risks related to diet, ranging
between 10 per cent and 70 per cent” (31).

He added that Doll/Peto acknowledged that occupational cancinogens
“tend to be those which increase the risk of some particular
type(s) of cancer very substantially,” and others might not
have been detected simply because they have not been investigated
or because the exposure concerned a small number of individuals, and
no suspicion was raised.

The end result is that cancers are attributed a “lifestyle”
cause with relative ease, while production and use of occupational
carcinogens continues unremarked and unabated. “The emphasis
given to lifestyle factors, to the detriment of information on the
role of chemical pollutants, favoured the uninterrupted production
of agents with negative effects on health that remain hidden or secret
or are deliberately underestimated,” said Tomatis. “Furthermore,
attributing most cancer cases to lifestyle, which is related to free
personal choice, unduly amplifies the individual’s responsibility,
diverts attention from the lack of commitment of health authorities
and obscures the aetiological role of other risk factors.”

Sir Richard Doll, lead author of the Doll/Peto report, played down
the occupational and environmental contribution to cancer throughout
the latter decades of his career, including actively opposing further
control measures. In a 1996 paper in the journal Carcinogenesis(38) he
wrote: “Two categories of cause remain for which I see little
possibility of material benefit from their further control, namely
the hazards of occupation and pollution.”

For several decades, however, Doll had “secret ties to industry”,
according to a report published online in the American Journal
of Industrial Medicine in November 2006 (39).
The professor, who died in 2005, was receiving substantial undeclared
payments from a number of chemical multinationals when he co-authored
the Doll/Peto report.

The AJIM study, ‘Secret ties to industry and conflicting interests
in cancer research’, concludes: “The most striking case
is that of Sir Richard Doll, co-author (with Richard Peto) of one
of the most influential papers in cancer epidemiology, one that concluded
that only a small percentage of cancer was caused by environmental
exposures.”

The AJIM analysis said Doll had a long term financial relationship
with Monsanto between 1970 and 1990, with evidence including a letter
from a Monsanto epidemiologist renewing Doll's contract for US$1,500
per day. This formed part of a dossier revealing Doll's relationships
with industry. In a paper dismissing vinyl chloride brain cancer risks,
for example, Doll did not disclose the £15,000 plus expenses
he had received from the Chemical Manufacturers’ Association
and the vinyl chloride manufacturers ICI and Dow.

The payments were confirmed in US court papers and in documents from
Doll’s own Wellcome Institute archive in London (40).

DEADLY OMISSIONS

What Doll/Peto missed

• Many cancers were missed entirely from their analysis
or designated not work-related, including melanoma and breast
cancer, the most common cancer among women.

• Overall risks to women would be under-estimated because
of their relatively late entry to the industrial workforce in
large numbers.

• Prostate cancer, the most prevalent cancer among men,
was only considered a risk for cadmium-exposed workers. Studies
have linked prostate cancer to exposure to pesticides, metalworking
fluids and other occupational exposures.

• The study only included 16 substances or industries
thought to be carcinogenic to humans, a small fraction the true
number.

• The report only considered mortality (deaths) and not
morbidity (number of cases), which is a considerably higher
figure – in the UK even Doll/Peto’s 4 per cent figure
would indicate around 11,000 cases a year.

• Excluding cancers in those over 65 years of age drastically
top-sliced the number of cancers considered, this measure alone
possibly reducing the work cancer toll to less than half the
true figure.

• Cancers in those working in small industries were excluded.

• The analysis excluded African-Americans, a group over-represented
in high risk jobs and with higher and increasing cancer rates.

• The analysis missed out those with indirect exposures
to carcinogens, for example maintenance workers in contact with
asbestos. These jobs are now among the highest risk for asbestos
cancer in the UK.

• The study only considered human evidence – but
for some substances and industries in the rapidly expanding
job market the studies hadn’t be done, and for many newer
exposures and industries conclusive human evidence just wasn’t
yet available, but there was strong suggestive evidence from
the more readily available toxicological and animal studies.
As a result many cancers caused or related to workplace exposures
would have switched columns to lifestyle, smoking or other causation
categories.

• The report acknowledged but failed to account for the
interaction of exposures, for example the greatly increased
risk of lung cancer in smokers who are also exposed to asbestos.
Most cancers are likely to result from a combination of exposures
or circumstances.

• Non-Hodgkin’s lymphoma, thought to be one of
the most common work-related cancers, was classified as having
only a slight risk association impacting on relatively few workers.

The 1981 Doll/Peto report, HSE’s preferred source for
its work cancer prevalence estimate, excluded breast cancer
– the most common cancer in women – from its analysis.

Studies have, however, linked breast cancer both to exposure
to substances and to shiftwork. A September 2005 report, 'State
of the evidence 2004: What is the connection between the environment
and breast cancer', analysed evidence from 21 studies published
since February 2003 and found links between exposure to radiation
and common industrial chlorinated chemicals, solvents including
ethylene glycol methyl ether and breast cancer risk.

An October 2005 report, 'Breast cancer – an environmental
disease: the case for primary prevention,' concluded there was
“incontrovertible evidence” that many industrial
chemicals and radiation are major contributors to overall breast
cancer rates.

A 2005 Harvard University study concluded working regular night
shifts increased dramatically the risk of a woman developing
breast cancer. The study, published online in the European Cancer
Journal “found a significant 48 per cent increase in the
risk of breast cancer among shiftworkers.”

Another report, published online on 31 May 2005 in the International
Journal of Cancer, concluded exposure to secondhand smoke increased
the risk of breast cancer by 70 per cent, and found half of
all these cases were linked to workplace exposures.

Stirling University’s Professor Andrew Watterson estimates
at least 500 and possibly more than a thousand breast cancer
deaths each year are related to occupation. He says the number
of new cases each year related to workplace factors is at least
1,500 and could exceed 5,000.

The workplaces that lent themselves to traditional epidemiology
– the largest industries with a stable workforce employed
for a long period – were by and large the preserve of
men. Effective surveillance for occupational cancer risk in
women has been relatively lacking. Different methods would be
necessary to determine occupational cancer risks with anything
like the certainty studies have allowed for traditionally male
jobs in heavy industry.

1. Doll R and Peto R. The causes
of cancer: Quantitative estimates of avoidable risks of cancer in
the United States today. Journal of the National Cancer Institute,
volume 66, number 6, pages 1191-1308, 1981.

29. Murray LR. Sick and tired
of being sick and tired: Scientific evidence, methods, and research
implications for racial and ethnic disparities in occupational health.
American Journal of Public Health, volume 93, pages 221-226, 2003.

31. Gennaro V and Tomatis L. Business
bias: How epidemiologic studies may underestimate or fail to detect
increased risks of cancer and other diseases. International Journal
of Occupational and Environmental Health, volume II, number 4, pages
356-359, October-December 2005 [pdf].

Related editorial: Egilman DS, Rankin
Bohme S. Over a barrel: Corporate corruption of science and its
effects on workers and the environment. International Journal
of Occupational and Environmental Health, volume II, number 4, pages
331-337, October-December 2005 [pdf]

33. Bridbord K and others. Estimates
of the fraction of cancer in the United States related to occupational
factors. Bethesda, MD: National Cancer Institute, National Institute
of Environmental Health Sciences, and National Institute for Occupational
Safety and Health, 1978.